Solar energy is one of the most widely used green energy sources, but the consumption of chemicals during the manufacturing of solar panels lowers the environmental value of this source. Therefore, in this study, we apply wire electrical discharge machining to the edge insulation process of solar cell chips to avoid the disadvantages of using chemical edge insulation and reduce the cost of waste liquid disposal. In addition, process parameters, such as servo voltage, feed rate, machining depth, discharge gap, droplet flow rate, and the concentration of abrasive powder added, are investigated to improve the surface roughness of specimens, as well as to remove the phosphorus layer and minimize cracks on the specimen surface. The experimental results indicate that the surface roughness of silicon chips can be reduced from 0.614 to 0.365 µm using deionized water with a droplet flow rate of 12 cc/min at the servo voltage of 30 V, which resulted in a 40% improvement in the surface roughness of silicon chips. The addition of 0.6 g/l SiC to deionized water further reduced the surface roughness to 0.304 µm, which represented a 10% improvement over the value achieved with pure deionized water. This means that the need for a chemical post-treatment process can be reduced while maintaining the surface quality of the specimen and ensuring environmental protection. At the same time, the removal of the phosphorus layer and cracks in one single process pass demonstrates that wire electric discharge machining can be used efficiently for wafer edge insulation.